The topics of the present research programs are: (1) the isolation and characterization of human chorionic gonadotropin-like (hGG-like) substance in tissues and biological fluids of normal subjects; (2) the generation and characterization of specific antisera against synthetic peptides based on the unique chemical structure of the hGGBeta subunit; (3) the development of picogram quantity assay method specific for hGG devoid of hLH interference; (4) the purification of chimpanzee chorionic gonadotropin (chGG) for the biological, chemical and immunological characterization.